By Healthcare Facilities Today

Changes to clarify requirements in a proposed ASHRAE standard to prevent legionellosis associated with building water systems are open for third public comment.

Standard 188P, Prevention of Legionellosis Associated with Building Water Systems specifies what must be done to control the spread of legionellosis. The standard helps facility managers understand how to apply the available information on Legionella effectively in order to prevent cases of legionellosis associated with building water systems.



Changes being proposed to the third review based on input received during a 2011 public review include:


•       Clarifications made to definitions in Section 3, Definition of Terms and a new term was defined.


•       Clarifications made to Section 5, Risk Characterization. Building characteristics were reorganized into subsections 5.2 and 5.3.

•       Reorganization of Table 1, Determining Preventative Measures Required for Buildings. The improvements reference two subsections of Section 5 (Sec 5.2 and 5.3).

•       Creation of a new subsection, 7.4, Water System Treatment and Management Program, in Section 7. Commenters indicated there should be specifications for a “water system treatment and management program” for buildings with none of the risk characteristics (now listed in Sec 5.2) but with any of the equipment specified (now listed in Sec 5.3).


•       Clarifications to Section 8 regarding wording, references, cited regulations and informative notes.

Compliance with the standard requires facility managers to formally take responsibility for controlling Legionella in their building water systems. This at the same time acts as a defense against accusations of negligence in those cases which are caused by the hazard from unknown sources, says ASHRAE.



Standard 188P also covers the potable water system in buildings, which are not treated as often as cooling towers, and will hold facility managers accountable for properly managing the entire building water system both potable and utility water.

The standard differs from ASHRAE Guideline 12, Minimizing the Risk of Legionellosis Associated with Building Water Systems, in that while the guideline gives recommendations about how to treat various building water systems, the standard specifies the practice of exactly what must be done with all those recommendations.



The proposed standard is currently open for a third public review from Jan. 25 to March 11, 2013. 

For more information and to comment.